Electrical switches



Jan. 1, 1957 B. v. KORRY ELECTRICAL SWITCHES 2 Sheets-Sheet 1 FiledApril 26, 1952 INVENTOR. BOP/5 l KGB/9V A r roe/v5 5 5 Jan. 1, 1957 B.v. KORRY 2,776,348

ELECTRICAL swrrcurzs Filed April 26, 1952 2 Sheets-Sheet 2 Ztw INVENTOR.BOP/5 1/. A OEPV A TTOEA/EV'S tates This invention relates to electricalswitches and more particularly concerns an improved gang switch of thedouble-throw, multiple-pole, snap-action type.

A general object of this invention is to provide such a switch in whichgreater compactness and simplified internal construction are achievedwhile external contact terminals are arranged accessibly and in a mannerbest suited for convenient circuit-wiring purposes. Preferably, and asherein described, such terminals and the corresponding internal switchcontacts are arranged in straight parallel rows for greateraccessibility, convenience and orderliness in the placement andarrangement of wires connected to the switch.

Additional objects concerning such a switch include a rugged and durableconstruction, reliable snap-action operation of the movable shuttlecarrying the slidable contact shoes, snap movement of the shuttleeffected near the end of a toggle actuator movement, and reduction ofmanufacturing costs through integration of parts and minimizing thenecessity of close tolerances and critical relationships in the switchconstruction.

A more specific object of the invention is a self-accommodating oradjusting shuttle and contact shoe arrangement tending to equalizecontact pressure of the switch contact shoes, and thereby equalize wearand insure longer and more satisfactory service of the switch.

In accordance with this invention a shuttle member guided for freelineal reciprocative movement in a switch casing is actuated betweenopposite limit positions by means of a spring-toggle mechanism includinga slidable actuating unit guided for movement in the housing parallel tothe shuttle member and interconnected therewith by an over-centeringtoggle spring and yoke assembly, the yoke ends swinging on fixed pivotsin the housing and being coupled by a slot-and-pin connection to theshuttle member. Rows of insulated switch contacts mounted in oppositeinner walls of the switch housing extend parallel to the line ofmovement of the shuttle member and are engaged in a selective manner byslidable contact shoes carried by such shuttle member as it is actuatedbetween its limit positions through manual shifting of the reciprocativeactuating unit one way or the other. Such slidable contact shoes areretained on the shuttle member for free movement laterally thereof,although, of course, constrained to follow the correct row of contactsto which they individually appertain. For each contact shoe engagingcontacts on one side of the switch housing there is a corresponding shoeengaging similar contacts on the opposite side of such housing, with acommon contact pressure spring interposed between and pressing suchopposed contact shoes oppositely against their respective stationaryswitch contacts. In effect, therefore, the pair of contact shoes andpressure spring float between opposite rows of stationary switchcontacts, resulting in a tendency for the contact pressures to beequalized. v

Preferably the switch casing or housing is of generally rectangularcross-sectional form, and the shuttle member 2,776,348 Patented Jan. 1,1957 2. is composed of spaced parallel insulating plates having guideapertures therein slidably receiving the legs or bent ends of U-shapedcontact slide shoes. The spacer elements maintaining predeterminedseparation of the insulating plates preferably comprise tubes in whichthe slide-shoe pressure springs are housed, the rows of stationarycontacts engaged by the slide shoes being inset in the opposite innerside walls of the housing, in the base of channel grooves constitutingguides for such U-shaped slide shoes.

As a result of the arrangement, the stationary contact terminals of theswitch lie in straight parallel rows on opposite outer sides of theswitch housing and are therefore readily accessible for Wiring purposesand may simply comprise machine screws threaded in the backs of theswitch contacts.

The foregoing and other features, objects and advantages of the improvedswitch will become more fully evident from the following detaileddescription of the presently preferredform thereof based upon theaccompanying drawings. It will be understood, however, that certain andbasic features of the improved switch construction may assume differentphysical forms and vary somewhat as to arrangement and detail within thescope of the invention and that the advancement which the inventionaffords is not necessarily limited tothe illustrative form.

Figure l is a perspective view of the improved switch with one side ofthe switch housing removed from the other, and with certain minor partsremoved, the actuating plunger or unit of the switch being shown in onelimit position.

Figure 2 is a perspective view of the switch with one section of thehousing removed from view and the actuating plunger in itsopposite'limit position relative to that in Figure 1.

Figure 3 is a top view of the switch with parts broken away in sectionalmanner to illustrate interior details.

Figure 4 is a longitudinal section taken on line 4-4 in Figure 3 withthe right-hand portion thereof broken away, and with parts about to snapover into the opposite limit position.

Figure 5 is a transverse sectional view taken on line 55 in Figure 4.

Figure 6 is a longitudinal section taken on a line which corresponds inlocation to the line 6-6 in Figure 4, but which extends through theright-hand portion of the switch as shown in Figure 3, to illustratecertain details of the switch actuating unit not appearing in Figure 4.

Figures 7, 8 and 9 are operational side views of the spring-togglemechanism in the switch and illustrate the principle of snap actioninvolved.

Figure 10 is an exploded perspective view of an assemblage including ashuttle-carried contact shoe pressure spring and a pair of contact shoesacted upon in common by this spring to engage oppositely locatedstationary contacts in the switch housing.

Figure 11 is a perspective view of a switch contact element.

The switch housingis preferably formed in three parts, a first sidesection 10 (Figure l), a bottom section ltlp shown connected to the sidesection lid, and a second side section 12, and is generally ofrectangular elongated form on all sides. These housing parts are made ofBakelite or other strong and durable insulating material preferablycapable of being machined and of being molded readily in the desiredconfiguration illustrated. Metal screws, not shown, and special fastenerbolts 14 are employed to secure the housing parts together with the edge12a in Figure 1 being the lower edge of the removable section 12 as itfits together with the remaining sections 10 and 10p.

In the molding of the plastic housing section 12 suitable ribs andbosses are formed on its inside wall to provide various stops, guidesand locating elements for the switch parts. For instance theconvergingly oriented rib edges 1 b and 12c form the sides of atoggle-yoke well and constitute stops establishing the opposite limitsof swing of the toggle yoke 16b. Similar edges 1% and 19c are formed inidentical locations on the inner wall of the complemental housingsection ll both housing sections having journal holes 12:. receiving therespective pivot pins 160 carried by the ends of the swingable U-shapedyoke 1617.

In the illustrated case two parallel grooves 122 and 12 are formed byribs on the inside wall of the housing section 12 and similar groovesltle and 1th in correspond ing locations on the opposite inner wall ofthe main housing section 1%) (Figures 1 and 2). Two rows of spacedelectrical contacts 18 are set into the bases of the respective groovesand the groove side walls serve as guides for the slide shoes 23engageable with such contacts, as will be more fully explainedhereinafter.

As part of an actuating unit 22, a slide plate 22a is adapted to slidefreely lengthwise of the housing upon its flat inside bottom wall,formed by the bottom section p (Figures 1 and 4). This slide plate isriveted or otherwise fastened to a cylindrical segment 22]) carried bythe inner end of a tubular actuating plunger 22c. The plunger is guidedfor longitudinal reciprocation in the housing through a front-endaperture therein formed by complemental semi-circular molded concavities10/2 and 12/1 in the respective housing parts. The maximum Width of theslide plate 220 between opposite longitudinal edges is only slightlyless than the internal width of the housing, so that these edges receivea measure of lateral guidance from the housing side walls duringlongitudinal reciprocation of the actuating unit 22, the type ofmovement by which the switch is actuated between opposite switchingpositions, as will more fully appear hereinafter.

A switch shuttle member 24 carrying the slide contact shoes 20selectively engageable with the stationary contacts 18 is likewiseguided in the housing for longitudinal reciprocation parallel to that ofthe actuating unit 22. This contact shoe carrier or shuttle member isformed of two insulating plates 24a and 24b, maintained in parallelspaced relationship by the short spacer tubes 24c extending between theinsulating plates at the locations of contact shoe pairs. The ends orlegs of the U-shaped contact shoes 29 slide in rectangular apertures24:? in the insulating plates and by their sliding fit in such aperturespermit lateral movement of the contact shoes toward and from the sidesof the shuttle member 24, that is in a direction normal to theirrespective planes of engagement with the rows of stationary contacts 18.A spring 242 is received in each of the tubular spacers 240, withinsulating disks 2d (Figure 10) interposed between the respective endsof the spring and the back sides of paired contact shoes 2% associatedtherewith. The arrangement is such that pressure of such paired opposite contact shoes against their respective stationary contacts 20 inany position of the shuttle member 2 longitudinally of the housing isestablished by a single spring 24e and is therefore equalized onopposite contacts. This is true because of the fact that the pairedslide shoes 20, the spring 24c and the insulating disks 24f- (Figure 10)are all slidably movable in and relative to the shuttle member at rightangles to the plane of contact of the stationary contacts 13. in elfect,therefore, the pairs of spring-urged contact shoes float betweenopposite sides of the housing and their carrier or shuttle member 24-serves merely as a positioner of the slide contact shoes 20 withrelation to each other and to the stationary contacts 13 lengthwise ofthe housing.

Guidance of the shuttle member 24 for longitudinal movement in turn iseffected largely by the lateral constraint which it receives from theslide shoes 29 as the latter are constrained to travel in theirrespective housing wall grooves 102, 1th, 126 and 12f. However, theupper edges of the insulating plates 24a and 2 .11 are adapted to slidealong the inside upper wall of the housing and their sides against thefaces of housing wall ribs forming grooves 162, 10 12a, and 12 foradditional guidance purposes.

A spring-toggle mechanism to including the yoke 16!; swingable on fixedpivots as already mentioned, operatively connects the actuating unit 22to the shuttle member Z -i to impart the desired snap action anddetaining spring efiect in the operation of the switch. Thisspring-toggle mechanism additionally includes (Figures 7 to 9) thecompression spring Me, an extensible spring bushing 16:! of atelescoping nature with enlarged ends flanged to constitute spring seatswith outer end faces recessed, and convexly rounded toggle bearings 16eand 16], one fixed to the transverse or upper side of the yoke 16b andthe other to the upper face of the slide plate 22a near the lattersinner end (Figures 1 and 7). Pressure of the preloaded spring 160continuously urges the extensible bushing ends 16d oppositely and intofirm retaining contact with the opposed bearings 16c and 16 carried bythe yoke and slide plate, respectively. The bearing 162 carried by theslide plate (Figure 7) is secured thereto by a rivet having the largecylindrical head 16f below the slide plate 22a and slidable in alongitudinal slot Mp in the housing extension 10p. The length of theslot is such, and its ends are so located, that such ends constitutestops, limiting travel of the slide plate 22a in desired extremepositions of the actuating unit 22. On the other hand, the limitpositions of swing of the yoke 16:) are established by the raised edges19b, 190, 1% and 120, as previously mentioned (Figure 1).

As shown best in Figure 2, the yoke 16b straddles the shuttle member 24as well as the spring assemblage 16c, etc., which is accommodatedbetween the opposite insulating plates 24a and 2412 near the inner endof such shuttle member. Linkage pins 16b, carried by the yoke sides,project inwardly therefrom through slots or open ings 24a and 24b in therespective insulating shuttle member plates. Thus arcuate swinging ofthe yoke between limit positions is converted into longitudinal movementof the shuttle member, the slots being of such shape as to permit thistransformation of movement. Accordingly, the snap-actionspring-detaining effect of the toggle applies to the shuttle member andgives the switch as a whole the desired positive snap action andspring-detention effect in the limit positions of the switch parts.

Figures 7, 8 and 9 illustrate more particularly the action of the springtoggle slide actuating mechanism. in each position of rest, as shown inFigures 7 and 9, the spring 16c reacts between the swinging yoke 16])and slide plate 22a to urge the yoke into one extreme position and theslide plate into the opposite extreme position. To reverse the positionsof these parts from those shown in Figure 7 to those shown in Figure 9,the slide plate is shifted toward the right to the position of Figure 8through almost its entire possible travel, moving spring 16c past itsdead center position in which a line joining the centers of itshemispherical bearings 16a and 16/ crosses the yoke 16b an appreciableamount. immediately the force of spring 160 swings the yoke 16b counterclockwise from the position of Figure 8 to the position of Figure 9.This action throws the pins Yb to the op posite side of the rectangularshuttle apertures 24!), whereupon they strike forcibly such oppositeside and drive the shuttle 24 abruptly into its opposite extremeposition of Figure 9. The spring force also completes the smalladditional travel of the slide plate 22a into its other limit positionshown in Figure 9 so that again the shuttle and slide plate occupyopposite limit positions. Thus positive snap action movement of theshuttle is accomplished only after the control knob 22 has been movedthrough almost its entire'pos sible travel.' I i The limit positions ofthe yoke 16b and: the shuttle member 24 are such that in one suchposition each of the slide shoes 20 bridges between two adjacentcontacts in one of the rows of contacts 18s or 18f, whereas in theopposite limit position these shoes bridge between a different pairofcontacts including one of those previously engaged. In other words theshuttle member travels approximatelythe distance between succeedingcontacts in moving" between its limit positions. During longitudinalshifting of the shuttle member elfected by the snap-action togglemechanism 16, the shoes 'having'ro'unded corners, slide smoothly anduniformly over the contacts and provide the desired guidance of theshuttle "unit as a whole inside the housing, as previously mentioned.

As shown'best in Figure 5, each stationary contact 1% is separatelymounted in a housing wall and its terminal for exterior electricalconnection is simply an outward extension or integral part of thecontact unit, being through a sleeve 18m and terminal screw 13p, so thatthe electrical continuity between the contact surface engaged by theslide shoe and the corresponding external terminal to which anelectrical conductor will be fastened, is exceptionally good. Moreoverthe arrangement of contact terminals in straight parallel rows outsidethe housing corresponds directly to the arrangement of contacts insidethe housing. As shown in Figure 11, the contact itself is a fiat platepreferably of silver, and is silver soldered tothe inner end of a tappedbrass sleeve 18m. The contact sleeve is held in position in the housingby spinning to a brass washer 18a, an operation which, with the washerand sleeve in place, flanges the outer edge of the sleeve over theinside edge of the washer to prevent the sleeve slipping inwardly of itshousing bore. A'terminal screw 18)) threads into the sleeve 18m and isprovided with a lock washer 18g.

An incidental feature of the illustrated form of the switch is anindicator arrangement including a lamp unit inthe translucent head 22@adapted to light up when external circuit conditions call for a reversalof the switch position. In case of fire in an airplane engine, forexample, the engine ignition circuit should be opened and a fireextinguisher circuit closed by reversing the switch actuator unit 22.The pilot or engineer would effect this switching operation inresponse'to illumination of the head 22a energized by an enginethermostat, for example.

To permit testing of a lamp bulb (not shown) suitably mounted inside thetranslucent switch actuator knob or head 22 the translucent button 22!:fits slidably in side a collar 22 which is threaded upon the outer endof the slide tube 220. By a suitable internal construction notillustrated in detail in these drawings, inward pressure against thebutton 22c relative to the collar 22 causing relative movementtherebetween, effects corresponding movement of a switch contact elementinside the tube 22c andcauses illumination of the lamp bulb inside thehollow button 22e. Energization of the lamp bulb to indicate anemergency condition takes place through terminals 22g suitably wired inan external circuit and slide rod conductors 22h slidably engageablewith such terminals to permit longitudinal reciprocation of the unit ZZinthe housing while the terminals 22g are fixed on the housing. Returnsprings 22:" encircling the rods 22h andsoldered at their opposite endsto the rods and terminals 22g respectively, serve also as conductorsinsuring electrical continuity in the energizing circuit for theindicator' lamp.

I claim as my invention:

, 1. An electrical switch comprisin'g an elongated switch casing, aseries of switch contacts arranged in rows extending longitudinally ofand in corresponding locations at opposite sides of said casing, ashuttle member guided for reciprocation longitudinally within saidcasing between the opposite rows of switch contacts, switch-closingcontact'element's carried by and extendin'g'transversely of saidshuttle'member to siida'blyengage corresponding opposite contactsselectively by reciprocation of said shuttle member, a switch-actuatingmember guided in said casing for longitudinal movement relative to saidshuttle member, stop means intereng'ageabie between said actuatingmember and the casing to limit movement of the actuating member in eachsense, a toggle lever having one end fixedly'pivotcd in the casing toswing about an axis transverse to the direction of reciprocation of theshuttle member and of the actuating member, stop means interengageablebetween said toggle lever and the casing to limit swinging of the togglelever in each sense, lost-mction means operatively connecting saidtoggle lever to said shuttle member to effect reciprocation of thelatter as the toggle lever completes its swinging from each limitposition to the other, and a preloaded compression spring strut havingone end pivotally engaging said actuating member and its opposite endpivotaily engaging the swinging end of said toggle lever, and reactingbetween the actuating member and the toggle lever to urge the samemutually apart and into opposite limit positions as the toggle leverswings past dead-center position in either sense, and through thelost-motion means urging the shuttle member sharply in the senseopposite to the sense of movement of the actuating member.

2. An electrical switch comprising an elongated switch casing, a seriesof'switch contacts arranged in a row longitudinally of said casing, ashuttle member guided for reciprocation longitudinally within saidcasing parallel to the row of switch contacts, a switch-closing contactelement carried by said shuttle member to slida'oiy engage contactsselectively by reciprocation of said shuttle member, a switch-actuatingmember guided in said casing for longitudinal movement relative to saidshut tle member, a toggle lever having one end fixedly pivoted in thecasing to swing about an axis transverse to the direction ofreciproocation 0f the shuttle member, stop means interengageaole betweensaid toggle lever and the casing to limit swinging of'the toggle leverin each sense, lost-motion means operatively connecting said togglelever to said shuttle member to eitect reciprocation of the latter asthe toggle lever completes its swinging from each limit position to theother, and a preloaded compression spring strut having one end pivotallyengaging said actuating member and its opposite end pivo-tally engagingthe swinging end of said toggle lever, and reacting between theactuating member and the toggle lever to urge the same mutually apartand into opposite limit positions as the toggle lever swings pastdeadcenter position in either sense, and through the lostmoticn meansurging the shuttle member sharply in the sense opposite to the sense ofmovement of the actuating member.

3. The electrical switch defined in claim 2, wherein the toggle levercomprises a. generally U-shaped yoke, the legs of which are pivoted inthe casing, and the crossbar whereof is at its swinging end, said springstrut beingmounted between such legs of the yoke to swing in alongitudinal plane of the casing therebetween.

4. The electrical switch defined in claim 3, wherein the actuatingmember comprises an element slidable directly aiong an inner wall of thecasing, a bearing ele ment thereon constituting the pivot for one end ofthe spring strut, and a like bearing element on the crossbar of thetoggle lever, constituting the pivot for the other end of the springstrut, pressure of such spring means maintaining said slidable elementin contact with said inner casing wall.

5. The electrical switch defined in claim 2, wherein the spring strutcomprises an elongated coil spring encircling an extensible springbushing having enlarged opposite ends constituting spring-end seats, atleast one of said enlarged bushing ends having a recessed outer end faceconstituting a pivot-bearing socket, and a pivotbcaring elementcomprising a pin with a rounded end engaged in said socket for pivotingmovement thcrebetween but unconnected thereto, pressure of said coilspring maintaining such engagement.

6. An electrical switch comprising a switch casing having parallelopposite sides, grooves in the inner faces of said sides disposed in aplane perpendicular to said switch casing sides, a switch contactmounted in each of said sides in the bottom of its respective groove andsaid contacts being located directly oppositely, a it ing shuttle memberreceived between said switch casing sides, reciprocable parallel theretobetween opposite limit positions and having apertures in its oppositesides spaced lengthwise of and in registry with such grooves in saidswitch casing sides, a pair of U shaped guide contact shoes having theirends received in said shuttle member apertures in opposite sides of saidshuttle member, respectively, holding said contact shoes and saidshuttle member against appreciable relative turning, and havingrectangular webs snugly received respectively in said grooves in saidswitch casing sides holding said shoes and said grooves againstappreciable relative turning and guiding said shuttle member forsubstantially nonrotativc movement lengthwise of said grooves by suchengagement therein, and spring means urging said contact shoes away fromsaid shuttle member and into engagement with said switch contacts in thebottoms of said grooves.

7. An electrical switch comprising a switch casing having parallelopposite sides, a row of switch contacts mounted in one of said sides, ashuttle member received between the opposite sides of said switchcasing, recipro cable lengthwise of said switch contact row betweenopposite limit positions, and including two spaced plates parallel tosaid switch casing sides and a plurality of spacer tubes extendingbetween said plates and maintaining them in such spaced relationship, aswitch contact shoe extending transversely across and beyond one end ofone of said tubes and engageable with adjacent switch contacts in saidrow for bridging therebetween, and a spring received in said spacer tubeand urging such shoe away from said shuttle member and into engagementwith the switch contacts in such row 8. An electrical switch comprisinga switch casing having parallel opposite sides, a row of switch contactsmounted in each of said sides at corresponding directly oppositelocations therein, a shuttle member received between the opposite sidesof said switch casing, reciprocable lengthwise of said switch contactrows between opposite limit positions, and including two spaced platesparallel to said switch casing sides and a plurality of spacer tubesextending between said plates and main taining them in such spacedrelationship, a pair of switch contact shoes disposed respectively atopposite ends of one of said spacer tubes and extending transverselyacross and beyond the ends of said tube and engageable with adjacentswitch contacts in said rows for bridging therebetween, and a springreceived in said spacer tube, interposed between said contact shoes andurging such shoes away from each other and into engagement with theswitch contacts in such respective rows.

9. An electrical switch comprising a switch casing having parallelopposite sides, switch contacts mounted in said sides, a shuttle memberreceived between said switch casing sides and reciprocable parallelthereto between opposite limit positions, a switch contact shoe carriedby said shuttle member in a position to slidably engage said switchcontacts, and means operable to move said shuttle member selectivelybetween opposite limit positions thereof, including a toggle leverhaving an end fixedly pivoted in said switch casing and operativelyconnected to said shuttle member to effect reciprocation thereofaccompanying swinging of said toggle lever, 21 switch-actuating memberguided in said casing for movement parallel to the course of movement ofsaid shuttle member, and an elongated preloaded compression spring strutextending transversely of the course of movement of said shuttle memberand having one end pivoted on said switch-actuating member and its otherend pivoted on said toggle lever adjacent to its swinging end, to urgesaid actuating member and said toggle lever into opposite limitpositions by movement of said switch-actuating member in one direction,and reversible at will by movement of said switch-actuating member inthe other direction, thereby effecting swinging of said spring strutthrough parallelism with said toggle lever and thus rendering iteffective to swing said toggle lever and said switch-actuating membereach toward its other limit position, producing opposite reciprocationof said shuttle member.

10. The electrical switch defined in claim 9, wherein the rows of switchcontacts are located in the bases of housing wall grooves, and the sidesof such grooves constitute guides for the contact shoes, defining thepaths of reciprocation thereof, and thereby guiding the shuttle memberfor reciprocative movement in the casing.

11. In a double-throw electrical switch such as includes a base, ashuttle element guided for lineal reciprocation thereof alongside saidbase between opposite limit positions and cooperative switch contactmeans carried respectively by said shuttle element and by said base andselectively interengageablc by such reciprocation of such shuttleelement, the improvement which comprises snap-action mechanism includinga movable actuating member guided by the base for reciprocationgenerally parallel to the line of reciprocation of said shuttle elementand likewise between opposite limits, and a toggle lever and a preloadedcompression toggle spring strut assembly having an effective line offorce extending generally transversely of said movable actuating memberline of reciprocation and including an actuating portion connected toand movable with said movable actuating member, and an opposite portionconnected to and movable with said shuttle element, said movableactuating member and said shuttle element normally occupying either ofcorrespondingly opposite limit positions respectively, with said togglelever and spring strut lines of force inclined at either of respectivelyopposite angles relative to the line of reciprocation of said actuatingmember, and reciprocation of said movable control member at will ineither direction from a given limit position thereof towards its otherlimit position effecting reversal of the angle of said toggle lever andspring strut, and thereby producing snap-action reversal of position ofsaid shuttle element and of the switch contact means carried thereby.

References Cited in the file of this patent UNITED STATES PATENTS1,807,398 Fleck May 26, 1931 1,863,523 Hammerly June 14, 1932 1,890,822Murray Dec. 13, 1932 1,965,125 Ketay July 3, 1934 2,373,889 Harmon Apr.17, 1945 2,521,561 Batcheller Sept. 5, 1950 2,574,290 Rowe Nov. 6, 19512,627,006 Lawson et al. Jan. 27, 1953 2,672,531 Stevenson Mar. 16, 1954FOREIGN PATENTS 119,716 Austria Nov. 10, 1930

